<!DOCTYPE html>
<html lang="en">
<head>
    <meta charset="UTF-8">
    <title>Title</title>
</head>
<body>
<script>
    var abc = [1,2,3];
    var bbb = [];
    // bbb = abc
    bbb.push(4)
    console.log(abc)
</script>
</body>
</html>
